*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
#box>li{
    display: inline-block;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: palevioletred;
    animation-name: box;
    animation-iteration-count: infinite;
    animation-timing-function: linear;
    animation-duration: 1s;
    animation-direction: alternate;
    list-style: none;


}
#box>li:nth-child(2){
    animation-delay: 0.3s;
}
#box>li:nth-child(3){
    animation-delay: 0.6s;
}

@keyframes box {
    0%{
        transform: scale(1);
    }

    100%{
        transform: scale(0);
    }
}








